![Page 1: Important notes - Engg. Diploma FY - Physics - Rectilinear Motion](https://reader036.vdocuments.site/reader036/viewer/2022081511/554e85dbb4c90573338b46c6/html5/thumbnails/1.jpg)
Rectilinear Motion
![Page 2: Important notes - Engg. Diploma FY - Physics - Rectilinear Motion](https://reader036.vdocuments.site/reader036/viewer/2022081511/554e85dbb4c90573338b46c6/html5/thumbnails/2.jpg)
Important Terms And Definitions
1. Kinematics : It is the branch of dynamics which deals
with the forces acting on bodies in motion without considering the mass of a body and the forces which is responsible to cause the motion.
![Page 3: Important notes - Engg. Diploma FY - Physics - Rectilinear Motion](https://reader036.vdocuments.site/reader036/viewer/2022081511/554e85dbb4c90573338b46c6/html5/thumbnails/3.jpg)
Rectilinear Motion
Motion of a particle along a straight line is called rectilinear motion, linear motion or one dimensional motion.
![Page 4: Important notes - Engg. Diploma FY - Physics - Rectilinear Motion](https://reader036.vdocuments.site/reader036/viewer/2022081511/554e85dbb4c90573338b46c6/html5/thumbnails/4.jpg)
3.
To describe linear motion of a particle its position at all times is to be specified. The equations used in this case are called ‘Equations of Motion’ or ‘Kinematical equations’.
![Page 5: Important notes - Engg. Diploma FY - Physics - Rectilinear Motion](https://reader036.vdocuments.site/reader036/viewer/2022081511/554e85dbb4c90573338b46c6/html5/thumbnails/5.jpg)
4. Every motion is related to the observer:
Position of a particle in motion is described in terms of distance from reference point or origin.
![Page 6: Important notes - Engg. Diploma FY - Physics - Rectilinear Motion](https://reader036.vdocuments.site/reader036/viewer/2022081511/554e85dbb4c90573338b46c6/html5/thumbnails/6.jpg)
Path length or distance travelled : The total distance covered by a particle
during its motion is called path length or distance traveled (scalar quantity)
![Page 7: Important notes - Engg. Diploma FY - Physics - Rectilinear Motion](https://reader036.vdocuments.site/reader036/viewer/2022081511/554e85dbb4c90573338b46c6/html5/thumbnails/7.jpg)
Displacement : Change in position of a moving particle
in a particular direction is called displacement. Displacement is the shortest distance between two positions of a moving particle in a particular direction (vector quantity)
![Page 8: Important notes - Engg. Diploma FY - Physics - Rectilinear Motion](https://reader036.vdocuments.site/reader036/viewer/2022081511/554e85dbb4c90573338b46c6/html5/thumbnails/8.jpg)
Displacement and distance traveled are equal in rectilinear motion but distance traveled is greater than displacement in any other motion.
![Page 9: Important notes - Engg. Diploma FY - Physics - Rectilinear Motion](https://reader036.vdocuments.site/reader036/viewer/2022081511/554e85dbb4c90573338b46c6/html5/thumbnails/9.jpg)
Average velocity (vector quantity)
The average velocity of a moving particle is defined as the displacement divided by the interval in which it has occurred
x
avg vel Vt
![Page 10: Important notes - Engg. Diploma FY - Physics - Rectilinear Motion](https://reader036.vdocuments.site/reader036/viewer/2022081511/554e85dbb4c90573338b46c6/html5/thumbnails/10.jpg)
Average speed : Average speed of a moving particle is defined as total distance travelled divided by time taken
Avg speed V = total distance traveled / time
![Page 11: Important notes - Engg. Diploma FY - Physics - Rectilinear Motion](https://reader036.vdocuments.site/reader036/viewer/2022081511/554e85dbb4c90573338b46c6/html5/thumbnails/11.jpg)
Acceleration : Acceleration of a moving body is defined as the rate of change of velocity with respect to time.
![Page 12: Important notes - Engg. Diploma FY - Physics - Rectilinear Motion](https://reader036.vdocuments.site/reader036/viewer/2022081511/554e85dbb4c90573338b46c6/html5/thumbnails/12.jpg)
Equation of motion, when Distance (s) Travelled by a Body Moving with a Uniform Velocity:
We know that, Distance travelled = Average velocity x time
we have, v = u + at, substitute this in equation (1), we get
u v
S t2
![Page 13: Important notes - Engg. Diploma FY - Physics - Rectilinear Motion](https://reader036.vdocuments.site/reader036/viewer/2022081511/554e85dbb4c90573338b46c6/html5/thumbnails/13.jpg)
![Page 14: Important notes - Engg. Diploma FY - Physics - Rectilinear Motion](https://reader036.vdocuments.site/reader036/viewer/2022081511/554e85dbb4c90573338b46c6/html5/thumbnails/14.jpg)
Equation of Motion, when Velocity of a Body Moving with Uniform Acceleration after Covering a Distance ‘S’
![Page 15: Important notes - Engg. Diploma FY - Physics - Rectilinear Motion](https://reader036.vdocuments.site/reader036/viewer/2022081511/554e85dbb4c90573338b46c6/html5/thumbnails/15.jpg)
Equation of Motion, when a Distance Travelled in nth Second by a
particle (or Body) Moving with Uniform Acceleration:
Consider a body in rectilinear motion moving with initial velocity (u) and uniform acceleration (a). In nth
second, it acquires a velocity (v) and covers a distance (s).
u = Initial velocity of a body: v = Final velocity of a body n = Number of second: sn = Distance travelled in n sec.
![Page 16: Important notes - Engg. Diploma FY - Physics - Rectilinear Motion](https://reader036.vdocuments.site/reader036/viewer/2022081511/554e85dbb4c90573338b46c6/html5/thumbnails/16.jpg)
sn-1 = Distance covered in (n – 1) sec.
snth = Distance travelled in nth sec.
= sn – sn-1
A = Uniform acceleration. From Equation (2), we have
For distance travelled in n second, put t = n
![Page 17: Important notes - Engg. Diploma FY - Physics - Rectilinear Motion](https://reader036.vdocuments.site/reader036/viewer/2022081511/554e85dbb4c90573338b46c6/html5/thumbnails/17.jpg)
For distance travelled in (n – 1) second, put t = n – 1
![Page 18: Important notes - Engg. Diploma FY - Physics - Rectilinear Motion](https://reader036.vdocuments.site/reader036/viewer/2022081511/554e85dbb4c90573338b46c6/html5/thumbnails/18.jpg)
![Page 19: Important notes - Engg. Diploma FY - Physics - Rectilinear Motion](https://reader036.vdocuments.site/reader036/viewer/2022081511/554e85dbb4c90573338b46c6/html5/thumbnails/19.jpg)
Graphical Representation
Velocity Time Graph Case I Uniform velocity Area under the curve = displacement S = Vt
![Page 20: Important notes - Engg. Diploma FY - Physics - Rectilinear Motion](https://reader036.vdocuments.site/reader036/viewer/2022081511/554e85dbb4c90573338b46c6/html5/thumbnails/20.jpg)
Case II:- When the body moves with a variable velocity:
If velocity varies from 0 to v, V-T diagram is a triangle as shown in fig. Here initial velocity (u) is zero.
Area under the graph = Area of a triangle
= s = distance travelled.
= s = distance travelled.
![Page 21: Important notes - Engg. Diploma FY - Physics - Rectilinear Motion](https://reader036.vdocuments.site/reader036/viewer/2022081511/554e85dbb4c90573338b46c6/html5/thumbnails/21.jpg)
s = distance travelled.
![Page 22: Important notes - Engg. Diploma FY - Physics - Rectilinear Motion](https://reader036.vdocuments.site/reader036/viewer/2022081511/554e85dbb4c90573338b46c6/html5/thumbnails/22.jpg)
If velocity varies from u to 0. (Final velocity (v) is zero): V-T
diagram is a triangle as shown in Area under the graph = Area of a rectangle
2
1OB OA
2
1u t
2
1v at t ....sinceu = v - at
2
10 at t ....since v = 0
2
1at
2
s distance travelled
![Page 23: Important notes - Engg. Diploma FY - Physics - Rectilinear Motion](https://reader036.vdocuments.site/reader036/viewer/2022081511/554e85dbb4c90573338b46c6/html5/thumbnails/23.jpg)
Negative sign indicates that there is retardation.
uSlope tan
t
ua .....since -a = retardation.
t
![Page 24: Important notes - Engg. Diploma FY - Physics - Rectilinear Motion](https://reader036.vdocuments.site/reader036/viewer/2022081511/554e85dbb4c90573338b46c6/html5/thumbnails/24.jpg)
If velocity varies from u to v: V-T diagram is trapezium as shown in fig. Area under the graph = Area of trapezium
![Page 25: Important notes - Engg. Diploma FY - Physics - Rectilinear Motion](https://reader036.vdocuments.site/reader036/viewer/2022081511/554e85dbb4c90573338b46c6/html5/thumbnails/25.jpg)